Option C is the correct option.
Drake avoids using technical jargon that kelly may be unfamiliar with.
Kelly has recently joined the Drake's Team, and is unfamiliar of the job and the job technicalities. So if Drake sends her an email, explaining the job details, full of jargon(technical words), she won't be able to understand that. So if Drake avoids using the professional language in his first email, that would show his good manners and etiquette.